The present invention relates to water-soluble, water-dispersible and crosslinked organic polymers bearing sulfonate groups, and in particular to polymers which contain recurring amide or urea linkages.
Water-soluble and water-dispersible polymers have proven useful in a wide variety of industrial applications. For example, such polymers are particularly useful as thickeners, flocculants and dispersants. Water-soluble and water-dispersible polymers are useful in oil field applications, such as enhanced oil recovery, well drilling, fracturing, acidizing, and the like; in mining, construction, paper manufacture, textile applications, and the like; in water based hydraulic and metalworking fluid applications; and in cosmetic, pharmaceutical, food processing, cleaning fluids, and the like.
Conventional water-soluble polymers are prepared by polymerizing water-soluble monomers such as acrylamide, sodium acrylate, and the like. The polymers are generally linear in nature and can behave as flexible coils in an aqueous solution. High molecular weight polymers generally have good thickening efficiencies. Therefore, in order for the skilled artisan to efficiently thicken aqueous fluids, it is generally necessary to employ polymers having the highest possible molecular weights. Unfortunately such polymers undergo a loss of viscosity during mechanical shear (i.e., mixing, filtering, injection, etc.) as well as experiencing a loss of desirable properties upon contact with ions in the aqueous medium, temperature changes, or other environmental conditions. Water-soluble polymers which are efficient thickeners and are capable of providing desirable properties in an aqueous medium virtually independent of temperature and salt concentration are desired.
Numerous sulfonated polyamides and polyureas are known in the art. See, for example, U.S. Pat. Nos. 3,839,294; 2,833,744; 3,567,632; 3,506,990; and 3,775,361. See, also, Silver et al., Journal of Polymer Science, Polymer Chemistry Edition, 17, 3519 (1979); Chauduri et al., Journal of Polymer Science, Polymer Chemistry Edition, 18, 2949 (1980); Vasileva et al., Vysokomol. Soedin., Series A, 14, 160 (1972); German Patent No. 1,067,212; and French Patent Nos. 2,212,356; 2,105,446; and 2,050,251. The physical properties and water compatibility of such polymers in aqueous media are not generally desirable.
Polymers which are highly water-soluble or water-dispersible are referred to collectively herein as water-compatible polymers. Because of the hydrophilic nature of these polymers, water generally permeates quickly through the polymers. Such polymers would be useful as pervaporation membranes, if the polymers could be treated so the material would maintain its integrity in the presence of liquid water.